1977 is the 20th year that the Department of Pediatrics, Baylor College of Medicine, has participated in the activities of the Southwest Oncology Group (SWOG). The initial purpose of this Group was to develop better methods of treatment for the control or cure of cancer in children. During the past few years multidisciplinary treatment programs have been developed and greater emphasis has been directed toward the etiology and pathophysiology of these diseases. This unit participates in all activities of the Pediatric Division. These activities include: Phase I studies of new chemical or biological agents; Phase II studies utilizing single or multiple agents in various disease categories; and Phase III studies, most of which are multidisciplinary, striving to determine the best combinations of therapy for control or cure of childhood cancer. Studies of the immunologic defects associated with various malignancies and immunotherapy directed toward eradication of various malignancies have been enlarged both within the Group and independently within this unit. Other areas of investigation relate to the epidemiology of malignant disease, the natural history of individual neoplastic disorders, and evaluations of methods to control the complications resulting from the disease or therapies. Particular emphasis has been given to determining prognostic factors and toward stratifying clinical case material accordingly in order to improve the basic study design. During the past three years the Group has been expanded in order to include radiotherapists, pathologists, and surgeons as active members and participants in all appropriate studies. The role of the biostatisticians, long participants in the chemotherapy studies, has been extended to involve all multidisciplinary activities.